Copper alloy material for electrical/electronic equipments, and electrical/electronic part

ABSTRACT

A copper alloy material for an electrical/electronic equipment, containing Ni 3.3 to 5.0 mass %, having a content of Si within the range of 2.8 to 3.8 in terms of a mass ratio of Ni and Si (Ni/Si), and containing Mg 0.01 to 0.2 mass %, Sn 0.05 to 1.5 mass %, and Zn 0.2 to 1.5 mass %, with the balance of Cu and inevitable impurities, wherein when a test piece with thickness t of 0.20 mm and width w of 2.0 mm is subjected to 90° W-bending with bending radius R of 0.1 mm, no cracks occur on the test piece; and, an electrical/electronic part obtained by working the same.

TECHNICAL FIELD

The present invention relates to a copper alloy material forelectrical/electronic equipments, and to an electrical/electronic part.

BACKGROUND ART

Parts of electrical/electronic equipments, for example, spring contactmaterials of connectors, are required to have properties, for example,mechanical strength, stress relaxation resistance, electricalconductivity, bending property, heat resistance, plating adhesiveness,and migration property. Conventionally, phosphor bronze has been used inmany cases, but phosphor bronze is not completely satisfactory in theproperties described above. Thus, beryllium copper, which is higher inmechanical strength and excellent in stress relaxation resistance, hasbecome used widely.

However, beryllium copper is very expensive, and metal beryllium isregarded as a substance of concern (SoC). Thus, Corson alloy(Cu—Ni—Si-based alloy), in which nickel (Ni) and silicon (Si) are addedto copper, has been attracted attention as an alloy that will substitutefor those materials.

Corson alloy is a precipitation-hardening-type alloy, which isstrengthened by dispersing and precipitating fine particles of Ni₂Siintermetallic compounds in Cu, and there have been reports on theattempts to enhance mechanical strength and electrical conductivity bydefining the amounts of addition of Ni and Si or the ratio of Ni/Si (seePatent Literatures 1, 2, and 3). Hitherto, it is considered, in regardto the Corson alloy, that the ratio of the contents of Ni and Si interms of percentage by mass, that is, the value of Ni (% by mass)/Si (%by mass) (hereinafter, indicated as Ni/Si), is preferably within therange around 4.2, which is a stoichiometric ratio of the Ni₂Si compoundthat mainly contributes to strengthening. Thus, the Ni/Si is within therange of Ni/Si of 3 to 7 in Patent Literature 1, within the range ofNi/Si of 3.5 to 5.5 in Patent Literature 2, and within the range ofNi/Si of 4 to 5 in Patent Literature 3. Further, Patent Literature 1describes, with concerns about a possible lowering of the electricalconductivity caused by solid solution of Si, that in order to reduce theamount of the solid solution of Si as less as possible, the amount of Niis preferably in slight excess compared to the Ni₂Si composition, andthat Ni/Si=4.5 is most preferred. Patent Literature 2 also describesthat the Ni/Si is preferably close to 4.2, which is the stoichiometricratio of Ni₂Si, with concerns about a possible lowering of theelectrical conductivity due to an increase in the amounts of solidsolutions of Ni and Si when the value of Ni/Si is away from 4.2.

{Patent Literature 1} JP-A-2001-181759 (“JP-A” means unexaminedpublished Japanese patent application)

{Patent Literature 2} JP-A-2006-233314 {Patent Literature 3}JP-A-2006-283059 DISCLOSURE OF INVENTION Technical Problem

However, as represented by those Patent Literatures, the Ni/Si in theconventional alloys has been such that, while the stoichiometric ratioof Ni₂Si, or a value corresponding to an excess amount of Ni compared tothe stoichiometric ratio of Ni₂Si, is considered preferable, thedefinition of the range of the ratio is broad and ambiguous. Further,investigations have been extensively made to maintain the balancebetween mechanical strength and electrical conductivity, but sufficientinvestigations have not been made on the conditions of obtaining highmechanical strength and favorable bending property.

Thus, the present invention is contemplated for providing a copper alloymaterial for electrical/electronic equipments, having a remarkably highmechanical strength and a favorable bending property, and anelectrical/electronic part utilizing the same.

Solution to Problem

The inventors of the present invention have found a region to makegrains finer and to enhance aging strength, at a side of Si in excess ofthe stoichiometric ratio of Ni₂Si even in the conventional Ni/Si range;and we have found that, although such a copper alloy slightly sacrificesthe electrical conductivity as compared with conventional Corson alloys,the copper alloy has an electrical conductivity that is higher than 12%IACS of phosphor bronze C5210 for springs and is equal to or higher than25% IACS of high-strength beryllium copper C17200, can retain sufficientelectrical conductivity for the use in connectors, and can retain highstrength and favorable bending property. The present invention hasattained based on these findings above.

According to the present invention, there is provided the followingmeans:

(1) A copper alloy material for an electrical/electronic equipment,containing Ni 3.3 to 5.0 mass %, having a content of Si within the rangeof 2.8 to 3.8 in terms of a mass ratio of Ni and Si (Ni/Si), andcontaining Mg 0.01 to 0.2 mass %, Sn 0.05 to 1.5 mass %, and Zn 0.2 to1.5 mass %, with the balance of Cu and inevitable impurities, whereinwhen a test piece with thickness t of 0.20 mm and width w of 2.0 mm issubjected to 90° W-bending with bending radius R of 0.1 mm, no cracksoccur on the test piece;(2) A copper alloy material for an electrical/electronic equipment,containing Ni 3.3 to 5.0 mass %, having a content of Si within the rangeof 2.8 to 3.8 in terms of a mass ratio of Ni and Si (Ni/Si), andcontaining Mg 0.01 to 0.2 mass %, Sn 0.05 to 1.5 mass %, Zn 0.2 to 1.5mass %, and one or more selected from the group consisting of Ag, Co,and Cr in a sum total of 0.005 to 2.0 mass %, with the balance of Cu andinevitable impurities, wherein when a test piece with thickness t of0.20 mm and width w of 2.0 mm is subjected to 90° W-bending with bendingradius R of 0.1 mm, no cracks occur on the test piece;(3) The copper alloy material for an electrical/electronic equipment asdescribed in item (1) or (2), which is produced by subjecting a castingot to a hot rolling, a dough (cold) rolling, and a solutiontreatment, followed by an intermediate (cold) rolling with rolling ratioof 5 to 50%, an aging at 400 to 600° C. for 0.5 to 12 hours, a finish(cold) rolling with rolling ratio of 30% or less, and a low-temperatureannealing, in this order;(4) The copper alloy material for an electrical/electronic equipment asdescribed in item (1) or (2), which is produced by subjecting a castingot to a hot rolling, a dough (cold) rolling, and a solutiontreatment, followed by an aging at 300 to 400° C. for 0.5 to 8 hours, afurther aging at 425 to 600° C. for 0.5 to 12 hours, a finish (cold)rolling, and a low-temperature annealing, in this order;(5) The copper alloy material for an electrical/electronic equipment asdescribed in item (1) or (2), which is produced by subjecting a castingot to a hot rolling, a dough (cold) rolling, and a solutiontreatment, followed by an intermediate (cold) rolling with rolling ratioof 5 to 50%, an aging at 300 to 400° C. for 0.5 to 8 hours, a furtheraging at 425 to 600° C. for 0.5 to 12 hours, a finish (cold) rollingwith rolling ratio of 30% or less, and a low-temperature annealing, inthis order;(6) An electrical/electronic part obtained by working a copper alloymaterial for an electrical/electronic equipment, with the copper alloymaterial containing Ni 3.3 to 5.0 mass %, having a content of Si withinthe range of 2.8 to 3.8 in terms of a mass ratio of Ni and Si (Ni/Si),and containing Mg 0.01 to 0.2 mass %, Sn 0.05 to 1.5 mass %, and Zn 0.2to 1.5 mass %, with the balance of Cu and inevitable impurities, whereinwhen a test piece of the copper alloy material with thickness t of 0.20mm and width w of 2.0 mm is subjected to 90° W-bending with bendingradius R of 0.1 mm, no cracks occur on the test piece; and(7) An electrical/electronic part obtained by working a copper alloymaterial for an electrical/electronic equipment, with the copper alloymaterial containing Ni 3.3 to 5.0 mass %, having a content of Si withinthe range of 2.8 to 3.8 in terms of a mass ratio of Ni and Si (Ni/Si),and containing Mg 0.01 to 0.2 mass %, Sn 0.05 to 1.5 mass %, Zn 0.2 to1.5 mass %, and one or more selected from the group consisting of Ag,Co, and Cr in a sum total of 0.005 to 2.0 mass %, with the balance of Cuand inevitable impurities, wherein when a test piece of the copper alloymaterial with thickness t of 0.20 mm and width w of 2.0 mm is subjectedto 90° W-bending with bending radius R of 0.1 mm, no cracks occur on thetest piece.

ADVANTAGEOUS EFFECTS OF INVENTION

The copper alloy material for electrical/electronic equipments of thepresent invention has an electrical conductivity that is higher than 12%IACS of conventional phosphor bronze C5210 for springs and equal to orhigher than 25% IACS of conventional high-strength beryllium copperC17200, thus has a sufficient electrical conductivity for the use inconnectors, and has a remarkably high mechanical strength and afavorable bending property. Further, since the electrical/electronicpart of the present invention is obtained by working the copper alloymaterial for electrical/electronic equipments, the part has a remarkablyhigh mechanical strength and also has a favorable bending propertyrequired for parts of the connector use.

Other and further features and advantages of the invention will appearmore fully from the following description.

BEST MODE FOR CARRYING OUT THE INVENTION

In the present invention, by setting the content of Ni to 3.3 to 5.0mass %, the resultant copper alloy material can have a favorable bendingproperty and a remarkably high mechanical strength. When the content ofNi exceeds the upper limit value, a coarse compound having no effects onmechanical strength is crystallized or precipitated, upon casting andhot-working, so that a mechanical strength appropriate for the contentis not obtained, and the hot-workability and bending property aredeteriorated. Further, when the content of Ni is less than the lowerlimit value, the electrical conductivity is enhanced, but the mechanicalstrength tends to be deteriorated.

Further, the Ni/Si (mass ratio of the contents) is defined to be withinthe range of 2.8 to 3.8. By setting the ratio within this range, sinceprecipitation of Ni₃Si₂ can be expected in addition to the precipitationof Ni₂Si and the precipitation densities of Ni₂Si and Ni₃Si₂ areincreased, the tensile strength is enhanced upon aging. Further, sincethe grain size upon the solution treatment can be controlled to besmaller as a result of an increase in the amount of solid solution ofSi, the grains also act satisfactorily in the bending property. When theratio is greater than the upper limit value, the required effect ofenhancing the strength upon the aging cannot be obtained. On the otherhand, when the ratio is less than the lower limit value, the requiredeffect of enhancing the strength upon the aging cannot be obtained, andthe electrical conductivity is lowered by the amount of solid solutionof Si is more noticeable than the effect of controlling the grain size,which exerts an adverse influence. A more preferable range of the Ni/Siis around 3.3, which is 3.0 to 3.5. When the ratio is in this range, amaterial can be obtained which is favorable in the balanced of thetensile strength, the electrical conductivity, and the bending property.

Mg improves the stress relaxation resistance, but its content is definedto 0.01 to 0.2 mass %, since when the content is less than 0.01 mass %,an improvement in the stress relaxation resistance cannot be seen, andwhen the content is greater than 0.2 mass %, Mg in such a too highcontent gives adverse affects on the bending property. The content of Mgis preferably 0.05 to 0.15 mass %.

Sn is interrelated with Mg, thereby to improve the stress relaxationresistance further. The content of Sn is defined to 0.05 to 1.5 mass %,because when the content is less than 0.05 mass %, the effects are notsufficiently obtained, and when the content is greater than 1.5 mass %,the electrical conductivity is lowered. The content of Sn is preferably0.1 to 0.7 mass %.

Zn slightly improves the bending property. Preferably, when the amountof Zn is defined to 0.2 to 1.5 mass %, the bending property can beobtained at a level that is free of problem for practical use even if Mgis added in an amount up to 0.2 mass % at the maximum. In addition tothat, Zn improves the adhesiveness of Sn plating or solder plating, orthe migration property. When the amount of Zn is greater than 1.5 mass%, the electrical conductivity is lowered. The content of Zn is morepreferably 0.3 to 1.0 mass %.

The copper alloy material of the present invention may also contain oneor two or more of Ag, Co, and Cr in 0.005 to 2.0 mass % in a total ofthose, in addition to the elements described above.

Ag improves the heat resistance and enhances the strength, and alsoinhibits coarsening of the grains, thereby to improve the bendingproperty. When the amount of Ag is less than 0.005 mass %, the effectsare not sufficiently obtained, and even if Ag is added in an amountgreater than 0.3 mass %, the production cost increases without anyadverse affects on the properties. From those points of view, thecontent of Ag is defined to 0.005 to 0.3 mass %.

Similarly to Ni, Co forms a compound with Si, to enhance the strength.When the content of Co is less than 0.05 mass %, the effects are notsufficiently obtained, and when the content is greater than 2.0 mass %,crystallization and precipitation products which do not contribute tothe strength are present even after the solution treatment, so that thebending property is deteriorated.

Cr precipitates as a second phase with Ni and/or Si, and is effective inthe control of the grain size. When the content is less than 0.05 mass%, the effects are not sufficiently obtained, and when the content isgreater than 1.0 mass %, the bending property is deteriorated.

In the case of adding two or more of Ag, Co, and Cr, the contents aredetermined within the range of 0.005 to 2.0 mass %, according to therequired properties.

The copper alloy material for electrical/electronic equipments of thepresent invention is preferably produced by the steps of: casting, hotrolling, dough rolling, and solution treatment, followed by intermediaterolling, aging, finish rolling, and low-temperature annealing.

The shape of the copper alloy material for electrical/electronicequipments of the present invention is not particularly limited, andexamples include sheet (plate), strip, wire, rod, and foil.

A preferred method of producing the copper alloy material of the presentinvention is explained in detail below. In the following, a method ofproducing a copper alloy sheet or a copper alloy strip is described indetail as a representative example.

In the present invention, the casting is conducted by a usual DC (directchill casting) method, or the like. It is preferable that, immediatelyafter conducting a homogenization treatment of the resultant ingot at atemperature of 850° C. to 1,000° C. for 0.5 to 12 hours, the hot rollingis conducted at a temperature of 700° C. to 950° C., followed by watercooling to prevent precipitation in the cooling. After the hot rolling,an oxide layer is face-milled, followed by the cold rolling.Hereinafter, this cold rolling is referred to as dough rolling. Thedough rolling is conducted to a sheet thickness, to give a given workingratio in the intermediate rolling and the finish rolling, respectively.

It is preferable that the solution treatment is conducted at amaterial's substantial temperature of 800° C. and 950° C., followed bymaintaining for approximately 3 to 6 seconds, and cooling with a coolingspeed of 15° C./sec or more (more preferably 30° C./sec or more) toprevent precipitation. When the solution treatment temperature is lowerthan 800° C., such problems occur that it is not possible to obtain asound recrystallized structure, to affect as negatively to the bendingproperty, and that the amounts of the solid solution of Ni and Si becomeinsufficient, to result in an insufficient precipitated amount of theNi—Si-based precipitation upon the aging, thereby to fail to obtain asufficient proof stress. When the solution treatment temperature ishigher than 950° C., coarsening of the recrystallized grains occur, tocause lowering of the strength, exhibition of an anisotropy, anddeterioration of the bending property.

As the intermediate rolling, a cold-rolling is conducted, to enhance thetensile strength and the proof stress upon the aging. Dislocations areintroduced into the matrix of the copper alloy upon the intermediaterolling, but a part of the dislocations function as the heterogeneousnucleation sites of the Ni—Si-based compound in the subsequent agingstep, aiding the formation of the compound at a high density with a finesize, and enhancing further the effect of increasing the precipitationdensity owing to the controlling of the Ni/Si. It is preferable tointroduce the intermediate rolling, to enhance the aging strength aswell; but if the rolling ratio is too high, the effect of enhancing theaging strength is saturated and the bending property is deteriorated.Thus, it is preferable to conduct the intermediate rolling within therange of rolling ratio 5 to 50%.

The aging makes it possible to precipitate and disperse the Ni₂Si andNi₃Si₂ compounds uniformly into the copper matrix, to enhance thestrength and improve the electrical conductivity. It is preferable toconduct the aging with a batch-type furnace, to maintain at a material'ssubstantial temperature of 400° C. to 600° C. for 0.5 to 12 hours. Whenthe substantial temperature is lower than 400° C., a quite longer periodof time is necessary to obtain a sufficient precipitation amount of theNi—Si-based compound, or the proof stress and the electricalconductivity result in insufficient. When the substantial temperature ishigher than 600° C., the Ni—Si-based compound becomes coarsened, to failto obtain the proof stress sufficiently.

Furthermore, when the aging is carried out in two stages of: aging at asubstantial temperature of the material of 300 to 400° C. for 0.5 to 8hours, and then aging at a substantial temperature of 425 to 600° C. for0.5 to 12 hours, it is possible to increase the precipitation density ofthe Ni—Si-based compound and to further enhance the strength and improvethe bending property. When this two-stage aging is carried out, theintermediate rolling may not be carried out; but by conducting theintermediate rolling, the strength can be further enhanced.

As the finish rolling, a cold-rolling is conducted to enhance the proofstress. When the proof stress after the aging is sufficient, it may bepossible to omit the finish rolling and the subsequent low-temperatureannealing. When the rolling ratio in the finish rolling is too high, thebending property is deteriorated and the stress relaxation resistance isdeteriorated. Thus, the finish rolling is preferably conducted with arolling ratio of 30% or less.

The low-temperature annealing is conducted to recover an elongation, thebending property, and a spring limit value, while maintaining thestrength in a certain degree. When the substantial temperature at thelow-temperature annealing is too high, recrystallization occurs, tocause lowering of the proof stress. Thus, it is preferable to conductthe annealing at the substantial temperature of 300 to 600° C. for ashort period of time of 5 to 60 seconds. When the substantialtemperature is lower than 300° C., the recovery of the elongation, thebending property, and the spring limit value becomes insufficient. Whenthe substantial temperature is higher than 600° C., it results inlowering of the strength.

Further, the electrical/electronic part of the present invention can beobtained by appropriately working the copper alloy material forelectrical/electronic equipments. This working method is notparticularly limited, and the part may be fabricated into a desired partshape in a usual manner, for example, by plastic working, such as pressworking.

EXAMPLES

The present invention will be described in more detail based on examplesgiven below, but the invention is not meant to be limited by these.

Example 1

Copper alloys having compositions shown in Table 1, were melt, followedby casting into ingots with thickness 30 mm, width 100 mm, and length150 mm, by the DC method, respectively. Then, the ingots were heated to900° C., to maintain at this temperature for 1 hour, followed by hotrolling to thickness 12 mm, and cooling immediately thereafter. Then,the oxide film layer was removed by face-milling the respective face in1.5 mm for each, followed by dough rolling to thickness 0.25 to 0.50 mm.Then, the resultant sheets were subjected to a solution treatment underany of conditions at 800° C. and 950° C., followed, immediatelythereafter, by cooling with a cooling speed of 15° C./sec or more. Then,the resultant sheets were subjected to intermediate rolling with rollingratio 5 to 50%. Then, the resultant sheets were subjected to aging at450 to 550° C. for 2 hours in an inert gas atmosphere, followed byfinish rolling with rolling ratio 30% or less, to adjust the final sheetthickness to 0.20 mm. After the finish rolling, the sheets weresubjected to a low-temperature annealing at 500° C. for 30 seconds, andthe thus-obtained materials were utilized to conduct the followingvarious property evaluations. Herein, the unit for elements of thecopper alloy (Ni, Si, and the like) indicated in the respective table isall percentage by mass (mass %), except for the value of Ni/Si (no unit)which is in terms of mass ratio.

Then, with respect to the copper alloy sheets produced in the above,investigation was carried out on (1) grain size, (2) tensile strength,(3) electrical conductivity, and (4) bending property. The results areshown in Table 1.

(1) The grain size was measured, according to JIS H 0501 (the cuttingmethod).(2) The tensile strength was measured with a No. 5 test piece asspecified in JIS Z 2201, according to JIS Z 2241. The tensile strengthwas indicated as a value rounded off to an integer multiple of 5 MPa.(3) The electrical conductivity was measured, according to JIS H 0505.(4) The bending property was measured, by providing a bending test piecewith width w of 2 mm and sheet thickness t of 0.20 mm, and conducting a90° W-bending test to the test piece with a bending radius R of 0.1 mm,so that a value of R/t would be 0.5. The test and evaluation methodswere carried out, according to the Japan Brass Makers Association,Technical Standard, “Evaluation on Bending Property of Thin Sheet andStrip of Copper and Copper Alloys” (JBMA T307:1999). As a result of thebending test, the test piece which had no cracks is judged to be goodand is given the symbol “∘” in Table 1, and the test piece which hadcracks is judged to be poor and is given the symbol “x” in Table 1.

TABLE 1 Grain Tensile Electrical Bending Elements size strengthconductivity property No. Ni Si Zn Mg Sn Others Ni/Si mm MPa % IACS R/t= 0.5 Example of 1 3.30 1.10 0.49 0.11 0.15 3.0 0.005 850 35 ∘ thisinvention 2 3.76 1.34 0.50 0.11 0.16 2.8 0.005 865 28 ∘ 3 3.74 1.01 0.510.10 0.16 3.7 0.007 865 32 ∘ 4 3.75 1.10 0.52 0.10 0.14 3.4 0.006 870 31∘ 5 3.73 1.06 0.53 0.11 0.14 0.05 Ag 3.5 0.006 875 31 ∘ 6 3.77 1.11 0.530.09 0.15 0.05 Co 3.4 0.005 875 31 ∘ 7 3.76 1.18 0.50 0.11 0.16 0.1 Cr,0.03 Ag 3.2 0.005 880 30 ∘ 8 3.75 1.14 0.49 0.11 0.15 0.1 Cr 3.3 0.005885 31 ∘ 9 4.98 1.47 0.49 0.10 0.15 3.4 0.005 935 30 ∘ 10 4.96 1.47 0.510.09 0.15 0.1 Cr 3.4 0.004 945 30 ∘ Reference 11 2.80 0.85 0.52 0.110.15 3.3 0.008 740 38 ∘ example 12 3.01 0.91 0.52 0.11 0.15 3.3 0.008785 38 ∘ Comparative 13 3.30 0.76 0.52 0.10 0.16 4.3 0.014 810 37 xexample 14 3.30 1.30 0.51 0.09 0.15 2.5 0.005 800 24 ∘ 15 3.74 0.83 0.500.10 0.15 4.5 0.015 825 36 x 16 3.75 0.81 0.51 0.10 0.15 0.05 Ag 4.50.014 830 36 x 17 3.74 0.83 0.50 0.11 0.15 0.05 Co 4.5 0.014 830 36 x 183.76 0.84 0.53 0.10 0.15 0.1 Cr 4.5 0.013 840 35 x 19 3.72 0.83 0.500.10 0.16 0.1 Cr, 0.03 Ag 4.5 0.013 845 34 x 20 3.75 0.96 0.50 0.11 0.163.9 0.012 850 37 x 21 3.75 1.39 0.52 0.10 0.15 2.7 0.005 855 25 x 223.77 1.63 0.49 0.10 0.15 2.3 0.004 815 24 x 23 4.90 1.07 0.51 0.11 0.174.6 0.014 900 30 x 24 4.92 1.89 0.50 0.11 0.15 2.6 0.005 890 24 x 255.10 1.13 0.50 0.10 0.16 4.5 0.014 890 29 x 26 6.03 1.84 0.51 0.12 0.153.3 Production was stopped, due to cracks occurred in hot-working

As shown in Table 1, Examples 1 to 10 according to the present inventionexhibited excellent characteristics in both of a remarkably high tensilestrength and a favorable bending property. Examples 1 to 10 according tothe present invention each had an electrical conductivity of 28% IACS orhigher, a tensile strength of 850 MPa or higher, and the bendingproperty with the value of R/t of 0.5.

Reference examples 11 and 12 had the Ni/Si within the defined range, butsince the amount of Ni was less than the lower limit value, they failedto exhibit such a remarkably high strength as in the examples accordingto the present invention. Comparative examples 13, 15 to 20, and 23,which had the ratios Ni/Si greater than the upper limit value, werelower in the mechanical strength, as compared with those of the examplesaccording to the present invention having the correspondingcompositions, respectively. Furthermore, since these comparativeexamples were large in the grain size, they were poor in the bendingproperty. Comparative examples 14, 21, 22, and 24, which had the ratiosNi/Si less than the lower limit value, were lower in the mechanicalstrength, as compared with those of the examples according to thepresent invention having the corresponding compositions, respectively,and furthermore these comparative examples were also poor in theelectrical conductivity. Comparative example 24 was also poor in thebending property. Comparative example 25, in which the amount of Ni waslarger than the defined range, was large in the particle size, and thebending property was poor. In Comparative example 26, due to the amountof Ni larger than the defined range, cracks occurred in the hot rolling,and thus the production thereof was stopped.

Example 2

Using the ingots of Nos. 4, 15, and 22, as produced in the above Example1, the results are shown in Table 2, in which investigations were madeon the effects of changing the post-solution treatment steps. Thenumbers shown in Table 2 are indicated such that, for example, when theproduction process was modified using the ingot No. 4, the instance isindicated with a sub-number such as 4-2.

Example 4-2 according to the present invention, and Comparative examples15-2 and 22-2 were produced, in the same production process as describedin the above Example 1, except for changing the aging to a two-stageaging treatment to conduct aging at 350° C. for 2 hours and then agingat 500° C. for 2 hours. Example 4-3 according to the present invention,and Comparative examples 15-3 and 22-3 were produced, in the sameproduction process as described in the above Example 1, except for notconducting the intermediate rolling immediately before the agingtreatment, and changing the aging to a two-stage aging treatment toconduct aging at 350° C. for 2 hours and then aging at 500° C. for 2hours. Reference example 4-4 was a test example in which the sameproduction process as described in the above Example 1 was carried out,except for not conducting the intermediate rolling immediately beforethe aging treatment, and changing the aging to a single stage agingtreatment at 500° C. for 2 hours, which is a comparative example withrespect to the invention according to the item (3) above.

The investigation on the properties was carried out, with respect to thecopper alloy sheets, in the same manner as in the above Example 1, on(1) grain size, (2) tensile strength, (3) electrical conductivity, and(4) bending property. The results are shown in Table 2.

TABLE 2 Grain Tensile Electrical Bending Elements size strengthconductivity property No. Ni Si Zn Mg Sn Others Ni/Si mm MPa % IACS R/tThis  4-2 3.75 1.10 0.52 0.10 0.14 3.4 0.006 920 33 ∘ invention  4-33.75 1.10 0.52 0.10 0.14 3.4 0.006 895 32 ∘ Reference  4-4 3.75 1.100.52 0.10 0.14 3.4 0.007 860 29 x example Comparative 15-2 3.74 0.830.50 0.10 0.15 4.5 0.015 855 35 x example 15-3 3.74 0.83 0.50 0.10 0.154.5 0.015 840 35 x 22-2 3.77 1.63 0.49 0.10 0.15 2.3 0.004 850 25 x 22-33.77 1.63 0.49 0.10 0.15 2.3 0.004 835 25 x

Examples 4-2 and 4-3 according to the present invention each hadachieved a further higher mechanical strength than Example No. 4according to the present invention of the above Example 1, and afavorable bending property.

Contrary to the above, Comparative examples 15-2 and 15-3, which had theNi/Si larger than the upper limit value, were lower in the mechanicalstrength with no effects of modifying the process, as compared toExamples 4-2 and 4-3 according to the present invention; and since theywere larger in the grain size, they were poor in the bending property.Comparative examples 22-2 and 22-3, which had the Ni/Si less than thelower limit value, were low in the electrical conductivity, and low inthe mechanical strength, as compared to Examples 4-2 and 4-3 accordingto the present invention with no effects of modifying the process.Further, Reference example 4-4, which was a test example in which thefinish rolling ratio was increased so as to try to enhance themechanical strength, but the resultant strength was rather lowered, andthe bending property was poor.

INDUSTRIAL APPLICABILITY

The copper alloy material for electrical/electronic equipments of thepresent invention has a remarkable high mechanical strength and afavorable bending property, and thus can be favorably used in parts forelectrical/electronic equipments, particularly in spring contacts ofconnectors, and the like. Furthermore, since the electrical/electronicpart of the present invention is one obtained by working the copperalloy material for electrical/electronic equipments, the part isfavorable as a part for the use in connectors, where a favorable bendingproperty is required, despite of having a remarkably high mechanicalstrength.

Having described our invention as related to the present embodiments, itis our intention that the invention not be limited by any of the detailsof the description, unless otherwise specified, but rather be construedbroadly within its spirit and scope as set out in the accompanyingclaims.

This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2008-092315 filed in Japan on Mar. 31,2008, which is entirely herein incorporated by reference.

1. A copper alloy material for an electrical/electronic equipment,containing Ni 3.3 to 5.0 mass %, having a content of Si within the rangeof 2.8 to 3.8 in terms of a mass ratio of Ni and Si (Ni/Si), andcontaining Mg 0.01 to 0.2 mass %, Sn 0.05 to 1.5 mass %, and Zn 0.2 to1.5 mass %, with the balance of Cu and inevitable impurities, whereinwhen a test piece with thickness t of 0.20 mm and width w of 2.0 mm issubjected to 90° W-bending with bending radius R of 0.1 mm, no cracksoccur on the test piece.
 2. The copper alloy material for anelectrical/electronic equipment according to claim 1, which is producedby subjecting a cast ingot to a hot rolling, a dough (cold) rolling, anda solution treatment, followed by an intermediate (cold) rolling withrolling ratio of 5 to 50%, an aging at 400 to 600° C. for 0.5 to 12hours, a finish (cold) rolling with rolling ratio of 30% or less, and alow-temperature annealing, in this order.
 3. The copper alloy materialfor an electrical/electronic equipment according to claim 1, which isproduced by subjecting a cast ingot to a hot rolling, a dough (cold)rolling, and a solution treatment, followed by an aging at 300 to 400°C. for 0.5 to 8 hours, a further aging at 425 to 600° C. for 0.5 to 12hours, a finish (cold) rolling, and a low-temperature annealing, in thisorder.
 4. The copper alloy material for an electrical/electronicequipment according to claim 1, which is produced by subjecting a castingot to a hot rolling, a dough (cold) rolling, and a solutiontreatment, followed by an intermediate (cold) rolling with rolling ratioof 5 to 50%, an aging at 300 to 400° C. for 0.5 to 8 hours, a furtheraging at 425 to 600° C. for 0.5 to 12 hours, a finish (cold) rollingwith rolling ratio of 30% or less, and a low-temperature annealing, inthis order.
 5. A copper alloy material for an electrical/electronicequipment, containing Ni 3.3 to 5.0 mass %, having a content of Siwithin the range of 2.8 to 3.8 in terms of a mass ratio of Ni and Si(Ni/Si), and containing Mg 0.01 to 0.2 mass %, Sn 0.05 to 1.5 mass %, Zn0.2 to 1.5 mass %, and one or more selected from the group consisting ofAg, Co, and Cr in a sum total of 0.005 to 2.0 mass %, with the balanceof Cu and inevitable impurities, wherein when a test piece withthickness t of 0.20 mm and width w of 2.0 mm is subjected to 90°W-bending with bending radius R of 0.1 mm, no cracks occur on the testpiece.
 6. The copper alloy material for an electrical/electronicequipment according to claim 5, which is produced by subjecting a castingot to a hot rolling, a dough (cold) rolling, and a solutiontreatment, followed by an intermediate (cold) rolling with rolling ratioof 5 to 50%, an aging at 400 to 600° C. for 0.5 to 12 hours, a finish(cold) rolling with rolling ratio of 30% or less, and a low-temperatureannealing, in this order.
 7. The copper alloy material for anelectrical/electronic equipment according to claim 5, which is producedby subjecting a cast ingot to a hot rolling, a dough (cold) rolling, anda solution treatment, followed by an aging at 300 to 400° C. for 0.5 to8 hours, a further aging at 425 to 600° C. for 0.5 to 12 hours, a finish(cold) rolling, and a low-temperature annealing, in this order.
 8. Thecopper alloy material for an electrical/electronic equipment accordingto claim 5, which is produced by subjecting a cast ingot to a hotrolling, a dough (cold) rolling, and a solution treatment, followed byan intermediate (cold) rolling with rolling ratio of 5 to 50%, an agingat 300 to 400° C. for 0.5 to 8 hours, a further aging at 425 to 600° C.for 0.5 to 12 hours, a finish (cold) rolling with rolling ratio of 30%or less, and a low-temperature annealing, in this order.
 9. Anelectrical/electronic part obtained by working a copper alloy materialfor an electrical/electronic equipment, with the copper alloy materialcontaining Ni 3.3 to 5.0 mass %, having a content of Si within the rangeof 2.8 to 3.8 in terms of a mass ratio of Ni and Si (Ni/Si), andcontaining Mg 0.01 to 0.2 mass %, Sn 0.05 to 1.5 mass %, and Zn 0.2 to1.5 mass %, with the balance of Cu and inevitable impurities, whereinwhen a test piece of the copper alloy material with thickness t of 0.20mm and width w of 2.0 mm is subjected to 90° W-bending with bendingradius R of 0.1 mm, no cracks occur on the test piece.
 10. Anelectrical/electronic part obtained by working a copper alloy materialfor an electrical/electronic equipment, with the copper alloy materialcontaining Ni 3.3 to 5.0 mass %, having a content of Si within the rangeof 2.8 to 3.8 in terms of a mass ratio of Ni and Si (Ni/Si), andcontaining Mg 0.01 to 0.2 mass %, Sn 0.05 to 1.5 mass %, Zn 0.2 to 1.5mass %, and one or more selected from the group consisting of Ag, Co,and Cr in a sum total of 0.005 to 2.0 mass %, with the balance of Cu andinevitable impurities, wherein when a test piece of the copper alloymaterial with thickness t of 0.20 mm and width w of 2.0 mm is subjectedto 90° W-bending with bending radius R of 0.1 mm, no cracks occur on thetest piece.